Carburetor for internal combustion engines



Aug. 22, 1933. J. WHEELER CARBURE'IOR FOR INTERNAL COMBUSTION ENGINES Filed Oct. 19, 1929 6 Sheets-Sheet 1 Irzeenier Jesse Wheeler.

J. WHEELER CARBURETOR FOR INTERNAL COMBUSTION ENGINES Aug. 22, 1933.

Filed Oct. 19, 1929 s Sheets-Sheet 2 fizz/entw- .2222? ll/lzeeler.

Aug. 22, 1933. J. WHEELER QARBURETOR FOR INTERNAL COMBUSTION ENGINES 6 Sheets-Sheet 3 Aug. 22, 1933. J. WHEELER ,180.

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed on. 19, 1929 e Sheets-Sheet 4 Ira/enter .fisse wheeler.

Aug. 22, 1933., VJ. WH-EELER 1,923,180

CAHBURETOR FOR INTEIRNAL COMBUSTION ENGINES- Filed Oct. 19, 1929 6 Sheets- Sheet 5 Jesse Wheeler.

.lltarm y.

CARBURETOR FOR INTERNAL COMBUSTION ENGINES Filed Oct. 19, 1929 6 Sheets-Sheet s iZyJZ- 27.

Inventor 35 Jesse Mlzaeler.

Patented Aug. 22, 1933 PATENT OFFICE CARBURETOR FOR INTERNAL COM- BUST ION ENGINES Jesse Wheeler, Long Beach,'Calif., assignor of one-half to Lang Transportation Company, Vernon, Calif., a copartnership consistin of Mike Lang, Gene Lang, and l-loward M. Lang Application October 19, 1929. Serial No. 400,874

' 44 Claims. .(Cl. 123-133 My invention relates to carbureting' devices, for internal combustion engines, and particularly to such mechanisms for effecting a feeding of the combustible gases under pressure.

One of my objects is to so regulate the fuel feed that delivery of a combustible mixture is made to the intake manifold of the motor at sufllcient velocity and pressure to just overcome the vacuum created on the intake stroke of the 0 pistons. In other words, the delivery into the cylinders, on the intake strokes of the pistons,

is positive, at substantially atmospheric pres-- fuel to the intake manifold under pressure, the

greatdifficulty encountered has been in timing, regulating and adjusting the pumps, and their driving means--as to velocity and capacity-with such precision that at all times the proper amount of combustible mixture will be delivered without flooding the carburetor. It has been with a view to'overcoming this difficulty that I have conceived and perfected the principles embodied in the herein disclosed mechanism.

In the means I employ I provide a pump, in

connection with a carburetor or mixing chamber,

F geared in timed relation with the main shaft of the motor, to supply the necessary pressure feed of the liquid fuel to the mixing chamber; this being designed, with respect to its size, capacity and velocity, as near as may be, in accordance with the size, speed and fuel requirements of the motor; a rotary valve, which is also geared with the'main motor shaft, to effect delivery of liquid fuel to the mixing chamber only on the suction stroke of the piston; and an intermediately disposed, automatic, by-pass member, containing a plurality of fluid pressure actuated by-pass valves, and including means for variably adjusting the pressure resistance of these valves, to be opened by the pressure of the fuel feed, in direct ratio to the extent of opening of the throttle valve and the speed of the motor.

As'I will more fully hereinafter point out,.my mechanism automatically supplies the proper amount of liquid fuel to the mixing chamber, proportionately to the speed of the motor, any ex cess delivered by the pump being automatically by-passed back to the fuel reservoir.

In addition to the above features I also employ a mixing chamber, including a hot spot, to effect complete vaporization of the liquid fuel, and also .60 a plurality of positively driven propellers, to insure a complete combustible mixture and proper delivery of the mixture to the intake manifold.

One clear distinction between my improved device and prior, similar devices, wherein pump mechanisms have been employed to effect a forced fuel feed, is that, by the means I employ, I am enabled to deliver a combustible mixture to the motor cylinders, on the intake stroke, at at least atmospheric pressure, without depending upon the vacuum created by the pistons on their intake strokes for-drawing the mixture into the cylinders, and to do. so without flooding the mixing chamber and without running the risk of incomplete vaporization of the liquid fuel due to such flooding. In the prior, similar devices, where pumps'have been employed, due to the fact that these cannot be accurately regulated and adjusted to nicely supply the needs of the motor at difierent speeds, an excess of fuel is delivered to 0 the mixing chamber, causing flooding, which also results in forcing the liquid fuel into the cylinders before complete vaporization has been accomplished. This not only results in waste of fuel, but also in inefficient operation of the motor with a consequent loss of power. With my arrangement the pump may, and probably does, normally deliver an excess of fuel over that required for operation of the motor at a given speed, yet, with my automatic feed regulating device, only a given quantity of liquid fuel will reach the mixing chamber, the excess being by-passed back to the fuel reservoir.

I In the following specificationI will more particularly point out themerits and advantages of my improvement, together with a detailed description of the structure and operation of preferred embodiment, this embodimentl'being illustrated in the accompanying drawings and referred to in the specification. In the draw-- ings- Fig. 1 is a side elevation of a typical internal combustion engine, showing the manner in which my improved device is applied thereto;

Fig. 2 is a top plan view of my arrangement, taken as indicated by the line 2--2 of Fig. 1;

Fig. 3 is a central vertical section taken through the carburetor, as indicated by the line 3-3 of Fig. 2;

Fig. 4 is a plan section, taken as indicated by the line 44 of Fig. 3;

Fig. 5 is also a plan section, taken as indicated by the line 55 of Fig. 3;

Fig. 6 is a sectional view taken as indicated by the line 6-6 of Fig. 4.; v

Fig. 7. is a longitudinal, vertical section taken through the automatic by-pass member, as indicated by the line '77 of Fig. 2, showing the adjusting rod in the position it occupies when the throttle valve is partly open;

Fig. 8 is a view similar to Fig. 7, only showing the position of the adjusting rod when the throttle valve is entirely open;

' Fig.9 is a transverse vertical section taken as indicated by the line 9-9 of Fig. '1;

Fig. 10 is a transverse vertical section taken as indicated by the line 1010 of Fig. '7;v

- Fig. 11 is a sectional view taken as indicated by the line 1111 of Fig. 2;

Fig-12 is a sectional view through'the rotary valve, taken as indicated by the line 12-12 of Fig.- 25

Fig. 13 is a view also taken as indicated by the line 12-.12 of Fig. 2, showing the valve in a dif- Fig. 17 is a sectional view taken as indicatedv by the line 1'7-l'7 of Fig. 2; and

Fig. 18 shows diagrammatic layouts of several different positions of the 'by-pass valve adjusting rod.

Referring first to Fig. 1, the numeral 20 desig nates generally a typical--four-cylindeninternal combustion engine, and 21 its intake manifold, with which my carbureting .mechanism is con nected. In Figs. 1 and 2 I have illustrated in side elevation and plan, respectively, my complete assembly as it is applied to a motor. The major elements of my mechanism comprise a pump A,

the by-pass B, rotary valve'C and carburetor D, operatively connected and combined to produce the results herein set forth.

Taking the above elements and their operative connecting media, in the order of arrangement, a liquid fuel'feed pipe 22 leads from a suitable source of supply, such as a fuel tank or reservoir, and discharges into a small auxiliary reservoir or chamber 23. The auxiliary reservoir is adapted to contain only asmall quantity of liquid fuel and is merely for the purpose of retaining a sufficient supply of fuel at all times to start the motor. The fuel feed from the pipe 22 is into the top of the auxiliary reservoir 23 and the dis,-"

charge therefrom is by gravity, through a pipe 24, which connects with the feed side of the pump A. A pressure feed pipe 25 connects the disthe by-pass B back to the tank or reservoir from which feed pipe 22 leads, and connected into this is a similar return flow pipe 31, leading from a sired results.

return flow passage of the rotaryv valve C. A return fiow pipe 32 likewise connects with the return flow pipe and leads from a drainage cup 33 located at the bottom of the mixing chamber D. v v

The pumpA and rotary valve C may be operated from either the generator or half-time shaft of the motor, properly geared to obtain the de- In the present'case I have shown these members operated from the generator shaft coupled with the'shaft 34 at 35a.

Thepump A may be any one of the usual and I well-known types of circulating pumps, of either. gear or oscillating construction. It is operatively connected with shaft 35 through the medium of a shaft 36, revolubly journalled in a bearing sleeve 3'7, and spur gears 38 and 39 (Fig. 17). Inasmuch as the details of construction and operation of circulating pumps of this character are so well-known to those skilled in the art, it' is not thought'necessary to go further into these matters here, as the details of the pump structure, as such, form no part of my invention.

Therotary valve C is shown in detail in Figs. 12, 13, 14, 15 and 16. This consists of a rotor 40, revolubly mounted within a fiuid tight fitting recess 41 in a casing 42. The front end 43 is in the form of a removable cover plate, to admit of easy assembling and access to the rotor for replacement or repairs. The rotor is fixed upon an operating shaft 44, the latter being revolubly journalled in bearingbores 45 and 46 in the cover plate 43 and the casing 42, respectively. A

spur gear 47 is fixed upon shaft 44 and meshes with a smaller spur'gear 48 fixed upon shaft 35 (Fig. 11).

Gears 4'? and 48 are enclosed within a casing 49 interposed between and connected with the casing 42 and casing 50 ofthe'pump A (see'Fig. 2).

The rotor 40 has an annular channel or recess 51 in one face (Fig. 14) which is adapted to register with an inlet port 52, in casing 42, into which the feed pipe 27 is connected, so that at all times there is fuel under pressure within this channel. A pair of diametrically opposed arcuate apertures 53 and 54, substantially 90 in length and concentric to theaxis of the rotor 40, extend through the rotor, from channel 51, and are adapted to intermittently register with an outlet port 55 in cover] 43, into which the feed pipe 28 is connected, as shown in Figs. 12 and 13. Extending into the rotor 40 is a pair of diametrically opposed, peripheral recesses 56 and 5'7, also substantially in length, which are adapted to intermittently register with a port 58 into which the return fiow pipe 31 is connected.

Apertures 59 and 60 connect recesses 56 and 57 with the annular channel 51, so that at all times there is fluid under pressure within the recesses 56 and 57.

The rotor 40, driven through gears 47 and 48, is rotated at the same speed as the main motor shaft. As in a four-cylinder motor there are two intake strokes and two explosions upon each revolution of the main motor shaft, each of the apertures 53 and 54 will successively register with the port 55, during'each revolution, and recesses 56 and 57 will likewise'successively register with the port 58 during each revolution. The apertures 53 and 54 are each positioned to register with port 55, in timed relation with the intake strokes of the pistons, and intermediate these strokes the recesses 56 and 57 successively regis-- ter with ports 58, so that at all times a substantially even pump pressure may be maintained within the annular recess 51, apertures 53 and 54 and recesses 56 and 5'7 during operation of the motor. In this manner excessivepressure is not built up within the rotary valve, resulting in an excessive supply of liquid fuel being discharged into the carburetor D through the feed pipe 28.

The details of the by-pass B are illustrated in Figs. '7, 8, -9 and 10. This consists of a block 61 through which the main fuel feed passage 26 extends, and into one end of which the return feed pipe 30 is secured, to connect with a drainage passage 62 which extends substantially parallel with the passage 26. The plurality of bores 63a, 83b and 63c-extend upwardly from the bore 26 and connect with a bore 63 which likewise extends substantially parallel with the bore 26. Rates 63a, 63b and 630 are reduced at their ends adjacent the bore 26 to form valve seats 64 and restricted inlet passages 65. Bores 66, situated above the seats 64 (Fig. 9), connect bores 63a, 63b and 63c with the bore 62. An adjusting rod 6'7 ismounted longitudinally slidable in bore 63, the'latter being closed at one end by a plug 68 and provided at its opposite end with a packing gland 69, to insure a fluid tight seal during longitudinalmovement of the rod 6'7. Each of the inlet apertures or ports 65 is normally closed bya ball valve 70,-these being held normally seated.

by expansible helical springs '71 which are held under compression by similar'balls 72 engaging the rod 6'7. The under face of the rod 67 is provided with notches 73a, 73b and 730, having relatively elongated inclined faces 75a, 75b and 75c, respectively, adapted to be engaged by the balls 72 during longitudinal movement of the rod 67.

A screw 78 extending into a slot '79 (Fig. '7) serves to limit longitudinal movement of the rod 6'1. An aperture 80 may be provided between bores 63 and 62 to permit drainage of any leakage from the former into the latter. Screws 72a, having pointed inner ends, may be provided for increasing the normal compressive strength of springs '71.

'The rod 6'7 is operatively connected with the throttle valve lever .81 (Fig. 1) through the medium of a connecting rod 82 and a flexible joint 83, so that when the throttle valve is closed the rod 6'7 will be in the position illustrated in Fig. "7, and when the throttle valve, is open it will be in the position illustrated in Fig. 8.

In Fig. 18 I have illustrated diagrammatically several positions of the rod 6'7 during operation.

The diagram designated E shows the relative positions :of the notches 73a, 73b and 730, andballs 72in bores 63a, 63b and 630, when the rod 6'7 is in its position corresponding to the closed position of the throttle valve 99. Diagram F illustrates the relative positions of these parts when the throttle valve is partly open, and diagram G shows their relative positions when the throttle valve is almost entirely open. In the diagram E, normally, the balls 72 in bores 63a and'63b rest within their respective notches 73a. and 73b,while at this time the spring '71 in bore 630 is held, by the ball 72 engaging the bottom face of the rod 67, to its maximum compression. The spring '71 in bore 63a is such that when the ball '72 is resting within the notch 73a. it will resist fluid pressure in the passage 26 up to from one and one-half to three pounds per square inch, and the ball '70 will be raised off its seat by a fluid pressure above that amount. When the spring '71 in bore 63a is compressed to its maximum, the coils will be substantially together and it will resist a fluid pressure up to twenty pounds or more per square inch. The spring '71 in bore 63b is heavier and has fewer convolutions than the spring in bore 63a so that normally, when its ball 72 is re'stingwithin the notch 7371 it will resist a pressure in the passage 26 up to five pounds per square inch and when compressed to its maximum, as shown in the diagram G (-Fig. 18) it will resist a fluid pressure in the passage 26 up to about twenty pounds per square inch. When the ball '72 in bore 63c is'in engagement with the bottom face of the rod 6'7, as shown in the diagram E, Fig. 18, its spring '71 is such that it will resist a fluid pressure in the passage 26 up to about twenty pounds per square inch,

and when its ball 72 is seated within its notch 730, as shown in thexdiagram F, Fig. 18, it will resist a fluid pressure upjto about ten pounds per square inch.

This by-pass arrangement is such that at starting or idling speed the fluid pressure required in the feed lineis from one and one-half to three pounds per square inch, and when the pressure in passage 26 raises above that amount it will be by-passed through the bores 65, 63a and 66, into the bore 62, and return to the storage tank through the return pipe 30. In case, at low speed, the pressure in passage 26 should rise up to and exceed five pounds per square inch,

' this excessive pressure would then also raise the ball 64, in bore 637), against the action of its spring '71, also permitting this excess of fluid to return to the storage tank through the bore 6.2 and pipe 30.. This provides'a safety by-pass and compensates for any slight inaccuracies in the strength of the springs in these two bores. As the throttle valve is opened the rod 67 is moved to the left, in Figs. '7, 8 and 18, compressing the springs 71 in bores 63a and 63b, checking against the increase in fluid pressure required to supply the motor needs. This movement is shown in the diagram F, Fig. 18, and also shows that the ball '72 in bore 630 has been forced upwardly into its notch 73c, thereby reducing the compression upon its complementary spring '71 to about ten pounds per square inch. Upon further opening of the throttle valve, necessitating further increased pressure to supply the motor needs, springs 71 in bores 63a and 637) will be further compressed, thus requiring an increased pressure inpassage 26 to effect by-passing of any fluid into the bore 62 and return pipe 30. I During this time any increase in pressure up to ten pounds per square inch, not required for motor operation, will be by-passed' through the bores 63a and 631). On further movement of the rod 6'7 by-passing, at any pressure, will be prevented through the bore 63a and the springs '71 in bores 63b and 630 will be correspondingly compressed so that it will require a correspondingly greater fluid pressure in passage '26 to by-pass any fluid therethrough. When compressed to their maximum, as illustrated in Fig. 8, springs '71, in bores 63b and 630 will resist fluid pressure in passage 26 up to about twenty to twenty-five pounds per square inch, which is about that required to supply fuel to the motor operating at its maximum speed. Should the pressure rise above this in passage 26,it will be by-passed, as before stated, through bores 63b and 630 the fuel reservoir.

and return line 30 to The carburetor D consists of a. casing 85 forming the mixing chamber 86;. the casing 85 being constricted at its upper end to form a tubular neck 87, this being provided at its upper end with a peripheral flange 88 by means of which it may be bolted to a complementary flange 89, of theintake manifold 21. The casing is preferably cylindrical and is closed at its bottom by means of a plate 91, removably secured thereto by screws 92, or other suitable means. A housing. 93, preferably formed integral with plate 91,.depends beneath the casing 85, this being more clearly shown in Figs. 4 and 5. A shaft 94, revolubly journalled at its lower end in a suitable ball bearing 95, in thebottom of housing 93, extends upwardly through a guide bearing 96, in plate 91, concentrically with the casing 85 and neck 87 (Figs. 3, 4 and 5). A propeller 97 is secured upon shaft94, with its horizontal center in a plane with the mouth or lower end of the neck 87,. as shown in Fig- 3, and a second propeller 98 is secured to the upper end of shaft 94 at a point as near the top of neck 87 as possible to permit proper action of the throttle valve 99, the latter being positioned at the extreme upper end 'of neck 8'? and operable through the medium of the lever 81 (Fig. 1). The pitch of the blades of propeller 98 is higher than the pitch of the blades of propeller 97, in the present case the blades of propeller 9'1 being shown at about 27, while the pitch of the blades of propeller 98 are about 5 higher, or 32. By this arrangement fluid pressure is not only created and a fluid flow effected through the neck 87, into the intake manifold, but this pressure is maintained .within the intake manifold 21 substantially constant. Shaft 94 is driven through the medium of a worm gear 100, keyed upon shaft 35, and a worm wheel 101 keyed upon shaft 94, within the housing 93; shaft 35 being revolubly journalled in suitable bearings 102 and 103 in opposite walls of the housing 93, as shown in Fig. 5.

An air intake aperture 104 is provided in one side of the casing 85, being equipped with an intake tube 105 in which there is a valve 106 for purposes of adjustment under certain conditions. A deflector plate 107 is placed over the intake aperture 104 to direct the incoming air, as indicated by the arrows in Fig. 4, around and spirally within the casing 85. This deflector plate 107 directs the incoming air around and over a hot spot 108 and the upper or discharge end 109 of the needle valve 29, situated directly therebeneath, both the hot spot 108 and the needle valve discharge end 109 being substantially diametrically opposite the air inlet 104.

The hot spot? 108 may be of any of the usual constructions, consisting of a metallic cap 111, secured to a base plate 112, and providing a space therein for the reception of the usual current resistant element (not shown) for genersting heat. Electrical conductors 113 and 114, one of which leads to a suitable source of electrical energy, such as a battery (not shown) and the other grounded upon the casing 85, as shown in Fig. 1,'connect with the current resistant element. Theseconductor's lead through a tubular stem 115, by means ofwhich the hot spot is mounted in, the casing wall 85, as shown in Fig. 3, suitable non-conductive material 116 being provided, surrounding the tube 115, to insulate it from the casing 85.

The needle valve 110 may be of any of the usual constructions, consisting of a tubular member 11'? extending upwardly through the housing 93 and screw-threadedly engaging a securing nut 118, in plate 91, as shown in 3.

by means of screws 128.

valve 131.

The feed pipe 28 is removably secured to a T fitting 119, on the lower end of the tube 117, by means of a suitable union 120. The usual adjustment for. the needle 121 is provided in a screw-threaded connection between itslower end 122 and a removable plug 123 in fitting 119; a knurled head 124 being provided on the bottom end of the needle for manual adjustment.

The upper end 109 of the needle valve is restricted, as at 125', to produce a spraying efiect, and the bottom face 126, of the hot spot 108, is inclined at an angle. to deflect the sprayed andvaporized gases outwardly into the casing 85, to be fully comingled with the incoming air,

and to be drawn upwardly and directed through the same as the area of the inlet passage into the engine manifold at 21. I

To take care of any. excess of fuel that may possibly gatherin the bottom'of the casing 85, and to avoid flooding of thecarburetor, the drainage chamber 33 is provided, depending from the plate 91 and removably secured thereto as A drain tube 129 is secured in thebottom plate 91 to drain into the chamber130 of cup 33, this being provided at its lower end with a gravity seated, non-return flop As liquid fuel gathers in the chamber 130 it will drain back to the storage tank through the return flow pipe 32.

In the operation of my device, assuming the motor to be at idling speed, the throttle valve 99. is partly opened as shown in Fig. 3 and the rod 67 is in the position diagrammatically illustrated at E in Fig. 18. In this position the spring '71 in bore 63c is compressed toits maximum, while the springs '71 in bores 63a and 631; are under their minimum compression. The rotor 40, of the rotary valve C, revolving at the same speed as the main shaft of the motor, delivers liquid fuel, under pressure, to the carburetor D in timed relation with the intake stroke of the pistons. It is, of course, to beunderstood that registration of the apertures 53 and 54, of the rotor 40, will be timed a little in advance of the actual opening of the intake valves, inorder to deliver the combustible mixture into the intake manifold at the proper time. When apertures 53 or 54' are not in registration with port 55 to deliver liquid fuel to the carburetor through feed pipe 28, one of the recesses 56-or 57 will be in registration with aperture 58 and delivering liquid fuel under pressure through return pipe 31 to the fuel tank; In this manner a substantially even pressureis maintained within the rotary valve, and there is no danger of building up a back pressure which will result in intermittently discharging an excess amount of liquid fuel into the carburetor.

In case the pump A delivers liquid fuel at a pressure in excess of that required for idling speed (assumingthe motor to be still operating at idling speed), that is, more than from about one and a half to'three pounds per square inch, this excess of pressure will raise the ball 70 in bore 63a off its seat, permitting the excess fluid to be by passed throughpassage 62 and return pipe 30 to the fuel reservoir. If the throttle valve is opened farther, resulting in increased speed of the motor and necessarily increased speed of the pump A and the delivery of fuel under higher pressure, the operation will be the same unless the pump delivers liquid fuel at a pressure in excess of five pounds per square inch, and more the rotary valve feed, at a higher pressure.

than enough to be by-passed through the bore 63a, the increase over five pounds per square inch will raise the valve oil its seat in bore 63b, so that this excess will be by-passed through both of the bores 63a. and 63b. If the throttle valve is further opened and the rod 67 moved toward the position shown in diagram F, Fig-18, and the fuel requirements of the motor be greater, the springs 71 in bores 63a and 63b will be further compressed, requiring a higher pressure in bore26 to raise the balls 70 off their seats, consequently fluid will be delivered to the carburetor, through When the rod 67 is in the position shown in diagram F, Fig. 18, it will require fluid pressure of between five and ten pounds per square inch to by-pass through the bores 63a and 63b, and as the ball 72 in bore 630 within its notch 73b, in rod 67, fluid will be by-passed through all three of the bores incase the fluid pressure raises above ten pounds per square inch. Further movement of the rod 67 to the position shown in diagram G, Fig. 18, will result in the spring 71 in bore 63 being fully compressed, closing that passage against any pressure, the excessive pressure thereafter being bypassed through bores 63b and 630. Under these circumstances the spring '71 in bore 63b will resist fluid pressure in passage 26 up to about twenty pounds per square inch, while the spring in bore 63c will resist fiuid pressure up to about fifteen pounds per square inch. Full movement of the rod 6'7, to fully compress all of the springs, as shown. in Fig. 8, will resist fluid pressure in passage 26 up to about twenty pounds per square inch.

As the liquid fuel is intermittently discharged into the carburetor D, through the needlevalve 29, it is sprayed upon the bottom face 126 of the "hot spot 108, thus not only diffusing it, but also vaporizing it to the fullest extent. The incoming air, through the inlet 104, being spirally directed around the mixing chamber 86, will fully mix with the vaporized liquid fuel and thence be drawn and-directed upwardly through the neck 87 by propellers 9'7 and 98. Propeller 97 being located in a plane at exactly the mouth of the neck 8'7 not only draws the vaporized gases toward the neckbut boosts them up into it, where they are further picked up and boosted by the propeller 98. The pitch of the blades of propellers 9'7 and 98 are such that a substantially constant fluid pressure is maintained within the manifold 21 during operation of the motor, and while the flow of fluid is intermittent, during operation of the motor, the discharges of liquid fuel into the carburetor are so close together that a substantially even flow of the combustible mixture is maintained in the manifold 21, without discharge of an excessive amount of liquid fuel into the carburetor.

While I have. herein shown and described the preferred specific embodiment of my invention, I do not thereby necessarily limit myself to details precisely as shown, but reserve the right to make such changes or modifications in structure as will come within the scope of the claims appended hereto. For instance, in adjusting my mechanism to motors of different sizes and speeds, and different fuel requirements, it is to be understood that the size and speed of rotation of the pump A may be varied, togetherwith its gearing connections; the size and speed of rotation, as well as the number of discharge apertures, of the rotary valve C may be varied; and also the size and capacity, as well as the number of by-pa'ss valves,

of the by-pass B, may be varied to suit particular conditions. Modifications of the needle valve may also be necessary, depending upon the type combination of: a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said feed pipe for feeding fuel to. the carburetor under pressure; valve means operatively connected in said feed pipe adapted to intermittently feed fuel to the carburetor; by-pass means operatively connected in said feed pipe, intermediate the pressure feed means and the valve means, adapted to automatically regulate the pressure of the fuel feed to the carburetor; there being a return flow pipe from the valve means to the to the reservoir.

3. In a device of the character described, the combination of: a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said feed pipe for feeding'fuel to the carburetor under pressure; a rotary valveoperatively connected in said feed pipe; a retum flow pipe connecting said valve and reservoir said valve being adapted tointermittently pass liquid fuel to the carburetor and into the return flow pipe to the reservoir; and means operatively connected in said fuel feed pipe, intermediate the pressure feed means and said valve, adapted to regulate the pressure of the fuel feed to the carburetor.

4. In a device of the character described, the combination of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said'reservoir and carburetor; means operatively connected in said feed pipe for feeding fuel to the carburetor under pressure; a rotary valve operatively connected in said feed pipe; a return fiow pipe connecting said valve and reservoir; said valve be and carburetor; means operatively connected in said feed pipe for feeding fuel to the carburetor under pressure; a rotary valve operatively connected in said feed pipe; a return flow pipe connecting said valve and reservoir; said valve being adapted to intermittently pass liquid fuel to the carburetor and into the return flow pipe to the reservoir; by-pass' means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the valve, adapted to regulate the pressure of the fuel feed to the carburetor;

and a return flow pipe leading from said by-pass means to the reservoir.

6. In a device of the character described, the combination of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said feed pipe for feeding fuel to the carburetor under pressure; a rotary valve operatively connected in saidfeed pipe; a return flow pipe connecting said valve and reservoir; said valve being adapted to intermittently pass liquid fuel to the carburetor and into theretum flow pipe to the reservoir; fluid pressure actuated by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the valve, adapted to automatically regulate the 7 pressure of the fuel feed to the carburetor; and a return flow pipe leading from said by-pass means to the reservoir.

'7. In a device of the character described, the combination of: a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressin'e of the, fuel feed to the carburetor; and a return flow pipe from said bypass means to the reservoir; said by-pass means having a plurality of spring-seated by-pass valves and means to vary the seating force of the valve springs. I

8. In a device of the character described, the combination of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting saidreservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; valve means operativelyconnected in said feed pipe adapted to intermittently feed fuel to the carburetor; by-pass means operatively connected in said feed pipe, intermediatethe pressure feed means and the valve means, adapted to automatically regulate the pressure of the fuel feed to the carburetor; there being a return flow pipe from the valve means to the fuel reservoir and a retm'n flow pipe from the by-passmeans to the reservoir; said by-pass'means having a pmrality of spring-seated by-pass valves and means to vary the seatmg force of the valve springs.

9. In a device of the character described, the combination of: a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; and a. return flow pipe from said bypass means to the reservoir; said b'y-pass means having a plurality of spring-seated by-pass valves, normally adapted tobe opened at difierent pressures, and means to vary the seating force of the valve springs.

10. In a device of the character described, the combination of: a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; by-pass means operatively connected in said 'fuelfeed pipe, intermediate the pressure feed means and the carburetor, adapted to; regulate the pressure of the fuel feed to-the carburetor; and a return flow pipe from said bypass meansto the reservoir; said by-pass means having a plurality of by-pass passages connecting said fuel feed pipe and said return flow pipe; valves in said passages; springs normally holding said valves in closed position, said springs each being adapted to yield to different fluid pressures in the fuel feed pipe.

11. Ina device of the characterdescribed, the combination of: a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel'feed to the carburetor; and a return flow pipe from the said by-pass means to the reservoir; said by-pass means having a plurality of by-pass passages conmeeting said fuel feed pipe and said return flow pipe; valves in said passages; springs normally holding said valves in closed position, said springs each being adapted to yield to different fluid pressures in the fuel feed pipe; and means to vary the seating force of the valve springs.

12. In a device of the character described, the combination of: a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said feed pipe for-feeding fuel to the carburetor under pressure; valve means operatively connected in said feed pipe adapted to intermittently feed fuel to the carburetor; by-pass means operatively connected in said feed pipe, intermediate the pressure feed means and the valve means, adapted to automatically regulate the pressure of the fuel feed to the carburetor; there being a return flow pipe'from the valve means to the fuel reservoir; a return flow pipe from the by-pass means to said reservoir; said by-pass means having a plurality of by-pass passages connecting said fuel feed pipe and said return flow pipe; valves in said passages; springs normally holding said valves in closed position, said springs each being adapted to yield to different fluid pressures in'the fuel feed pipe.

13.-In a device of the character described, the I combination of: a liquid fuel reservoir; a carmeans to the fuel reservoir and a return flow pipe from the by-pass means to said reservoir; said bypass means having a plurality of bypass passages connecting said feed pipe and said flow pipe; valves in said passages; springs normally holding said valves in closed position, said springs each being adapted to yield to different fluid pressures in the fuel feed pipe; and means to vary the seatingforce of the valve springs.

14. The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; .a carburetor; afuel feed pipe connecting said reservoir and carburetor; means opcratively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feedto the carburetor; a return flow pipe for said by-pass means to the reservoir; said by-pass means having a by-pass passage connecting said fuel feed pipe and said return flow pipe; a valve in said passage; a spring holding said valve normally seated; and means to vary the seating force of the valve spring.

15. The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir andcarburetonmeans operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; and a return flow pipe from said by-pass means to the reservoir; said by-pass means having a plurality of by-pass passages connecting said fuel feed pipe and said return flow pipe; valves in said passages; springs holding said valves normally seated, said springs each being adapted to yield to different fluid pressures in the feed pipe; and means to vary the seating force of the valve springs.

16. The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; bypass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; a return flow pipe from said by-pass means to the reservoir; said by-pass means having a by-pass passage connecting said fuel feed pipe and said return flow pipe; a valve in said passage; a spring holding said valve normally seated; and means to vary the seating force of the valve spring, said last named means being operative in timed relation with the throttle valve.

17. The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; bypass means operatively connected in said fuel feed pipe, intermediate thepressurc feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; a return flow pipe from said by-pass means to the reservoir; said by-pass means having a by-pass passage connecting said fuel feed pipe and said return flow pipe; a valve in said passage; a spring holding said valve normally seated; and means to vary the seating force of'the valve spring, said last named means being operative to increase the seating force of said valve spring in proportion to the opening movement of the throttle valve and vice versa. 1 18. The combination with an internal. combustion engine having a throttle valve, of a liquid fuel reservoir; acarburetor; a fuel feed pipe con necting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feed reservoir; said by-pass means having a plurality of by-pass passages connecting said fuel feed pipe and said return flow pipe; valves in said passages; springs holding said valves normally seated, said springs each being adapted to yield to different fluid pressures in the feed pipe; and means to vary the seating force of the valve springs, said last named means being operative in timed relation with the throttle valve.

19. The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor. under pressure; bypass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; and a return flow pipe from said by-pass means to the reservoir; said by-pass means having a plurality of by-pass passages connecting said fuel feed pipe and said return flow pipe; valves in saidpa sages; springs holding said valves normally seated, said springs each being adapted to yield to different fluid pressures in the feed pipe; and means to vary the seating force of the valve springs, said last named means being operative to increase the seating force of said valve springs in propor-' tion to the opening movement of the throttle valve and vice versa.

20. The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; a carburetor; a fuel feed pipeconv necting said reservoir and carburetor; means op eratively connected in'said fuel feed pipe for feeding fuel to the carburetor under pressure; a rotary valve operatively connected in said feed pipe; a return flow pipe'connecting said valve and reser-' voir, said valve being adapted to intermittently pass liquid fuel to the carburetor and into the return flow line to the reservoir; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; a return fiow pipe from said bypass means to the reservoL' said by-pass means having a by-pass passage connecting saidfuel feed pipe and said return flow pipe; a valve in said passage; a spring holding said valve. normally seated; and means to vary the seating force of the valve spring.

21, The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; a rotary valve operatively connected in said feed pipe; a return flow pipe connecting said valve and reservoir, said valve being adapted to intermittently pass liquid fuel to the carburetor and into the return flow line to the reservoir; by-pass means'operatively connected in said fuel feed pipe, intermediate the pressurefeed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; and a return flow pipe from said by-pass means to the reservoir; said by-pass means having a plurality of by-pass passages connecting said fuel feed pipe different fluid pressures in the feed pipe; and.

Y valve operatively connected in said feedpipe; a return flow pipe connecting said valve andreservoir, said valve being adapted to intermittently pass liquid fuel to the carburetor and into the return flow line to the reservoir; by-pass means operatively connected in said fuel feedpipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; a return flow pipe from said by-pass means to the reservoir; said by-pass means having a by-pass passage connecting said fuel feed pipe and said return flow pipe; a valve in said passage; a spring holding said valve normally seated; and means to vary the seating force of the valve spring, said last named means being operative in timed relation with the throttle valve.

reservoir, said valve being adapted to intermit-;

tently pass liquid fuel to the carburetor and into the return flow line to the reservoir; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; a return flow pipe from said by-pass means to the reservoir; said by-pass means having a by-pass passage connecting said fuel feed pipe and said return flow pipe; a valve in said passage; a spring holding said valve normally seated; and means to vary the seating force of the'valve spring, said last named means being operative to increase the seating force of said valve spring in proportion to the opening movement of the throttle valve and vice versa. a

24. The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; a carburetor; a fuel feedpipe connecting said reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; a

rotary valve operatively connected in said feed pipe; a return flow pipeconnecting said'valve and reservoir, said valve being adapted to intermittently pass liquid fuel to the carburetor and into the return flow line to the reservoir; by-pass means operatively connected in said fuel'feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate thepressure of the fuel feed to the carburetor; and a return flow pipe from said by-pass means totheres'ervoir; said by-pass means having a plurality of by-pass passages connecting said fuel feed pipe and said return flow pipe; valves in said passages, springs holding said valves normally seated, said springs each being adaptedtoyield to different fluid pressures in the feed pipe; and means to vary the seating force' of the valve springs, said last named means being operative in v timed relation with the throttle valve.

25. The combination with an internal combustion engine having a throttle valve, of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively conneoted in said fuel feed pipe for feeding fuel to the carburetor under pressure; a rotary valve operatively connected in said feed pipe; a return flow pipe connecting said valve and reservoir, said valve being adapted to intermittently pass liquid fuel to the carburetor and into the return flow line to the reservoir; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure 7 springs, said last named means being operative to increase the seating force of said valve springs in proportion to the opening movement of the throttle valve and vice versa. i

.26. The combination with an internal combustion engine having a throttle valve, of a carburetor; a liquid fuel reservoir; 2. fuel feed pipe connecting said carburetor and reservoir; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; fluid pressure actuated by-pass means operatively connected in said fuel feed line, intermediate the pressure feed means and the carburetor, adapted to automatically regulate the pressure of the fuel feed to the carbuetor; a return flow pipe connecting said by-pass means and the reservoir; and means to variably adjust the by-pass means to be actuated by different fluid pressures in the fuel feed pipe, said last named means being operative in timed relation with the throttle valve.

27. In a device of the character described, the combination of: a carburetor; means for feeding fuel to the carburetor under pressure; and means, intermediate the pressure feed means and the carburetor, for regulating the pressure of the fuel feed to the carburetor, said carburetor com- I prising a mixing chamber having an air intake aperture therein, a needle valve connected with the fuel feedline and discharging into the mixing chamber, a heating element in said mixing chamber positioned to be impinged by the discharge from the needle valve, and propeller means in said mixing chamber positioned to mix and discharge the combustible mixture from the mixing chamber.

28. In a device of the character described, the combination of a carburetor; means for feeding lfuelto the carburetor under pressure; and means, intermediate the pressure feed means and the carburetor, for regulating the pressure of the fuel feed to the carburetor, said carburetor com-, I prising a mixing chamber'having an air'intake aperture therein and having a constricted neck portion adapted to connect with the intake manifold of an internal combustion engine, a needle valve connected with the fuel feed pipe and discharging into the mixing chamber, a heating element in said mixing chamber positioned to be impinged by the discharge from the needle valve, and propeller means in said mixing chamber positioned to mix and discharge the combustiburetor; a fuel feed pipe connecting said fuel feed reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetor, adapted to regulate the pressure of the fuel feed to the carburetor; and a return flow pipe from said by-pass means to the reservoir; said carburetor comprising a mixingchamber having an air intake aperture, therein, a needle valve connected with the fuel feed line and discharging into the mixing chamber, a heating element in said mixing chamber positioned to be impinged by the discharge from the needle valve, and propeller means in said -mixing chamber positioned to mix and discharge the combustible mixture from the mixing chamber.

30. In a device of the character described, the combination of: a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said fuel feed reservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; by-pass means operatively connected in said fuel feed pipe, intermediate the pressure feed means and the carburetonadapted to regulate the pressure of the fuel feed to the carburetor; and a return flow pipe from said by-pass means to the reservoir; said carburetor comprising a mixing chamber having an air intake aperture therein andhaving a constricted neck portion adapted to connect with the intake manifold of an internal combustion engine a needle valve connected with the fuel feed pipe and discharging into the mixing chamber, a heating element in said mixing chamber positioned to be impinged by the discharge from the needle valve, and propeller means in said mixing chamber positioned to mix and discharge the combustible mixture from the mixing chamber, said propeller means comprising a shaft extending into the neck portion, means to rotate the shaft, propeller-blades on said shaft at the entrance to the neck portion, propeller blades on said shaft positioned in the neck portion above the first named propeller blades and having a higher pitch than said first named propeller blades, and a throttle valve positioned above said last namedpropeller blades. 7

31. In a device of the character described, the combination of 2 a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said feed pipe for feeding fuel to the carburetor under pressure; a rotary valve operatively connected in said feed pipe; a return flow pipe connecting said valve and reservoir; said valve being adapted to intermittently pass liquid fuel to the carburetor-and into the return flow pipe to the reservoir; said carburetor comprising a mixing chamber having an air intake aperture therein, a needle valve connected with the fuel feed line and discharging into the chamber. v 32. In a device of the character described, the

her, a heating element in said mixing chamber positioned to be impinged by the discharge from the needle valve, and propeller means in said mixing chamber positioned to mix and discharge the combustible mixture from combination of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting said reservoir and carburetor; means operatively connected in said feed pipe for feeding fuel tothe carburetor under pressure; a rotary valve operatively connected in said feed pipe; a return flow 1 pipe connecting said valve and reservoir; said valve being adapted to intermittently pass liquid fuel to the carburetor and into the return flow pipe to the reservoir; said carburetorjcomprising a mixing chamber having an air intake aperture therein and having a constricted neck portion adapted toconnect with the intake manifold of to mix and discharge the combustible mixture from the mixing chamber, said propeller means comprising a shaft extending into the neck portion, means to rotate the shaft, propeller blades 1 on said shaft at the entrance to the neck portion,

propeller blades on said shaft positioned in the neck portion above the first named propeller blades and having a higher pitch than said first named propeller blades, and athrottlevalve positioned above said last named propeller blades.

the mixing cham- 33. In a device of the character described, the

combination with an internal combustion engine of a carburetor; means for feeding fuel to the carburetor under pressure; and fluid-pressure-actuated means, intermediate the pressure feed means and the carburetor, for regulating the pressure of the fuel feed to the carburetor, the latter means embodying a by-pass having means adapted to present resistance to the fuel pres sure, and means'to automatically increase said resistance proportionately with increased speed of the engine.

34. In a device of the character described, the combination of: a carburetor; a throttle valve associated with the carburetor; means for feeding fuel to the carburetor under pressure; and means, intermediate the pressure feed means and the carburetor, for regulating the pressure of the fuel feed to the carburetor, the latter means embodying a by-pass having yielding means adapted to present resistance to the fuel, and means operatively connected with said throttle valve to increase said resistance of the yielding means.

35; In a device of the character described, the combination of: a carburetor; means for feeding fuel to the carburetor under pressure; and means, intermediate the pressure feed means and the carburetor, for regulating the pressure of the fuel feed to the carburetor, the latter means embodying plural by-pass channels having means adapted to normally present progressive stages of resistance to ,the pressure feed means, and means for increasing the resistance at the individual channels.

36. In a device of the character described, the combination with an internal combustion engine of: a carburetor;means for feeding fuel to the carburetor under pressure; and means, intermemmgulating the pressure of the fuel feed to fuel feed tothe carburetor, the latter means em- 7 bcdying plural by-pass channels having'means adapted to normally present progressive stages. of resistance to the pressure-feed means, and means operatively connected with said throttle valve for increasing resistance at the individual 38. In a device -of the character described; the ccmbmation of: a carburetor; means for feeding fuel to the carburetor under pressure; and means,

in'tflmediate the pressure feed means and the carburetor, for regulating the pressure of the fuel feed to the carburetor, the latter means embodying a bypass having a plurality of yielding means each adapted to present 'a different degree of resistance to the fuel pressure and means to control said plurality of yielding means.

, 39.".[n adevice of the character described, the combination of: a carburetor; means for feeding fuel to the carburetor under pressure; and means,

intermediate the pressure feed means and the carburetor, for regulating the pressure of the fuel feed to the carburetor, the latter means embodying plural by-pass channels and yielding means adapted to normally present progressive stages 7 of resistance to the pressure feed means, and

means for increasing the yielding resistance at the individual channels.

40. Ina device of the'character described, the

' combination of: a liquid fuel, reservoir; a car- 7 buretor; a fuel feed pipe connecting said reservoir and carburetor; means operativelyconnected in said fuel feed pipe forfeeding fuel to the carburetor under pressure; means operatively connected in said fuel feed pipe for regulating the pressure of the fuel feed to the carburetor; and a return flow pipe from said regulating means to the fuel reservoir, the last named means-embodying a plurality of adjustable yielding valves each adapted to present a different diate the pressure feed means and the carburetor,

range'of resistanceato thepassage of fuel to the return fiow pipe and means to control the resist- "ance ofsaidlplurality of valves.

41. In a device of the character described, the combination with an internal combustion engine of a liquid fuel reservoir; a carburetor; a fuel feed pipe connecting saidreservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel .to the carburetor under pressure; means operatively connected in said fuel feed pipe for regulating the pressure of the fuel feed to the carburetor;jand a return flow pipe from said regulating means to the fuel reservoir; the last named means embodying yielding means adapted to present resistance'to the passage of fuel to the return flow pipe and means to automatically increase said resistance proportionately'with increased speed of the engine.

42. In a device of the character described, the combination of: a liquid fuel reservoir; a carburetor; a throttle valve associated with said carburetor; a fuel feed pipe connecting saidreservoir and carburetor; means operatively connected in said fuel feed pipe for feeding fuel to the carburetor under pressure; means operatively connected in said fuel feed pipe for regulating the pressure of the fuel feed to the carburetor; and a return flow pipe from said regulating means to the fuel reservoir, the'last named means embodying yielding means adapted to present-resistance to the passage of fuel to the return flow pipe and means operatively connected with said throttle valve to increase said resistance.

43. The combination with a carburetor, of

means for feeding fuel to the carburetor under pressure; means adapted to intermittently feed fuel to the carburetor; and means for regulating I the pressure of the fuel feed to the carburetor, the last means embodying a by-pass having yielding means adapted to present resistance to the fuel pressure, and automatic means to increase said resistance.

44. The combination with a carburetor of: a throttle valve associated with the carburetor;

means for feeding fuel to the carburetor under pressure; meansadapted tointermittently feed fuel to the carburetor; and means for regulating'the pressure of the fuel feed to the carburetor, the last means embodying a by-pass having valve means adapted to be opened by pressure of the fuel feed, and means operatively connected with saidthrottle valve to control the resistance of said valve means.

JESSE WHEELER.

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